Added User Object to REST API
Merge pull request #43 from this-username-is-taken/user

Added User Object to REST API
Set default LOGIN_URL.
Add DeliveryBucket model.
Enhance delivery bucket admin to be able to assign order.
Add DeliveryBucketManager for convenience constructor.
Limit driver choice to the users have driver group.
Add DeliveryWindowAdmin and action for create DeliveryBucket from DeliveryWindow.
Add Order inline admin to DeliveryWindowAdmin.
Update DeliveryBucket to use assignee and add assignor.
Show assignee name in __unicode__
Add auth check for destination and stats page.
Add number of orders count to the admin list.